The former Downing Street director of communications dismissed the claims by Major General Michael Laurie in a letter to Sir John Chilcot, the chairman of the Iraq inquiry.

Campbell intervened after Laurie, who was director general in the Defence Intelligence Staff, claimed in secret evidence to the Iraq inquiry that the purpose of the arms dossier in September 2002 was "precisely to make a case for war, rather than setting out the available intelligence".

In his letter to Chilcot, Campbell challenged Laurie on three grounds:

• "I do not know and have never met Major General Laurie, and was not aware of any involvement he might have had in the September 2002 dossier on Iraq's WMD."

• "Neither I – nor, so far as I am aware, anyone else in Downing Street – was made aware of his views at the time, or at any time in the subsequent nine years, until he felt moved to write to you, and his letter was published."

• "Witnesses who were directly involved in the drafting of the dossier have made clear to several inquiries that at no time did I put anyone in the intelligence community under pressure, or say to them or anyone else that the then prime minister's purpose in publishing the dossier was to make the case for war."

Campbell added that he had intended to refrain from making any comments on the evidence of other witnesses to the inquiry. But he added in his letter to Chilcot: "Given Major General Laurie's letter was aimed at my evidence to you, however, and given the scale and nature of the allegations it led to at home and overseas, I would appreciate the opportunity to place the above on record to the inquiry."

Tony Blair's former communications director decided to challenge Laurie's evidence, published by the Iraq inquiry last week, after it sparked renewed claims that Andrew Gilligan's controversial BBC Today programme broadcast was correct. Gilligan famously reported that the government had inserted a claim that Iraq could launch a WMD attack within 45 minutes "probably" knowing that it was untrue.

Kevin Marsh, editor of the Today programme at the time, told the Independent last week: "The thing that rankles with me a little bit is that I thought at the time when Andrew Gilligan came with the story was that it wasn't just broadly correct, it was 100% correct. Here's the guy at the very top of the [Defence Intelligence Staff] saying: 'We knew we were being pushed to find a certain bit of evidence and it was being presented in a certain way' and that's exactly what Andrew said in his story."

Campbell says that evidence at the inquiry into the suicide of David Kelly, Gilligan's source, disproved the BBC's central claim – that Downing Street inserted intelligence into the dossier knowing it to be false.